This is the handle of the original uploader or encoder, a common practice in the "warez" and release community to identify the source of the rip.
Always scan .rar files with updated antivirus software, such as Malwarebytes, before extracting, as archives from third-party sources can occasionally contain unwanted scripts or malware. D0sS0nMlt1tud.m720p.yamil.part3.rar
You cannot open or play Part 3 on its own. If you are missing Part 1 or Part 2, the extraction process will fail. This is the handle of the original uploader